OpenEuphoria

Re: Euphoria Code Optimiser

• Posted by Robert Craig <rds at EMAIL.MSN.COM> Mar 21, 1998
• 872 views

Daniel writes:
> By the way Rob (if you are still reading)
> are calculations with constants in
> optimised at compile-time ?
> eg
> constant my_num=396
> sequence bar
> for a=1 to very_big do
>    bar={1,2,3}/my_num
>    grill(bar)
> end for
> compiles
> <snip>
> bar={ 0.002525252525253, 0.005050505050505,
> 0.007575757575758}
> <end snip>

It would be easy to add "constant folding" into
Euphoria's optimizer, but it hasn't been done yet
because I rarely see a time-critical section of code
where a programmer repeatedly calculates with
constant values. People are smart enough to perform
the calculation once and assign the result to a
variable or constant, or at least move the calculation
out of an inner loop.

I've been tempted many times in the past to add this,
but there just don't seem to be enough cases in practice
where it actually matters. Before adding any optimization
to Euphoria, I like to scan through my directory of user
contributions to see how often the optimization would
actually pay off. That way I avoid making the compiler
more complicated without any real benefit.

Your other idea of making a pre-processor that converts
inefficient Euphoria code into efficient Euphoria code
sounds interesting.

Regards,
     Rob Craig
     Rapid Deployment Software

P.S. The 2.0 Official Release will be out in
less than a week. Please send any last-minute bug reports
to:  rds at msn.com  Thanks.